Guys... I know I have been blowing this forum up with questions about my 86 W250 to Magnum 5.9 swap but I have another timing question. The Magnum was initially computer controlled timing so there isn't much of a timing mark to speak of (5 degrees plus and minus)... so there in lies the rub. I should be looking at about 10-15 BTC base timing right? So is there a good trick for getting this right with only 5 degrees showing on the timing marks? For reference I am using the stock distributor from the 86 and this is not a hot rod... just a 4x4 offroad rig. She has stock cam and an Eddy 650 offroad AVS carb. I have it set right now at 5 and it runs ok but I know that it should be advanced more.

I had the thought to manually rotate the engine to TDC and take some whiteout or soapstone and make a "second timing mark" on the harmonic balancer at 5 degrees ATC so that when I am timed 5 before my new mark will show TDC and I can now adjust it to 5 degrees before and viola I have a total base of 10 BTC. If this is totally crazy please say so or if there is another easy trick out there I would be happy to hear it. I am open to all suggestions. The truck comes back from getting exhaust tomorrow so I will be timing it then or possibly Tuesday. Thanks in advance for advice!

I would verify TDC, and put a timing tape on the dampner

Yeah, timing tape. Or twist it until it runs the way it should, not very scientific, but this is how all my engines get timed sooner or later.

Very very easy to make timing marks. Use a piston stop and scribe new marks I've never used tape in my life because I'm a cheap SOB. The thing with "boughten" tape is you have to make sure it's for the right size dampener and so many of these outfits are in "Chivvy" mode.

You can easily degree the dampener out to wherever you want. Just carefully measure around it after you make TDC and figure how many "degrees per inch," then figure how many degrees is 40. Measure carefully what this is and mark it, using a small flex tape. Then use dividers to mark this in half for 20, etc.

This one is definitely more of a "twist it till it runs right" kind of project... However I do appreciate all the in depth advice on timing. Will be very beneficial for future projects where knowing the timing is much much more critical. ie... the 383 '70 challenger build my brother and I are working on.

Factory timing marks were ok when we had Good gas... Today. ethanol gas oxygenated gas The motor need 5-10 deg more timing

Your best bet is to get an Advancing timing light...Then you can dial in the timing setting you want and turn the dist. until the mark comes up on TDC..Very easy and saves a ton of hassle...Bill

Hassle, time, and money are always a juggling act. I often opt to save myself time and hassle here lately and let a little money go.

If you knew someone that you could borrow it from it would be nice...If not they are around $60-$70 for the cheaper ones and go up from there...The one I have is digital and cost around $350...And it wont work on MSD because it is a digital spark...And digital to digital freaks the thing out...I found out from MSD tech line...The timing was jumping all over the place so I called them and they told me why...Bill

I've done the 5 degrees and mark, another 5 = 10 then put a hacksaw blade cut or center punch mark in the damper, then another 10 and so on. It has been accurate enough to get going 'cause you'll probably get total and if it pings you can back it off a couple which you can estimate between the 5's.

This will work if your confident your original TDC mark is accurate.

Bill, I only have an associates in Electronics Engineering but that sounds a wee bit like a copout to me... Spark is Spark. It's all created by the collapsing of the magnetic field in the coil... the only difference is how that charging and collapsing is controlled and how much voltage is induced. I would say either MSD ignitions produce so much voltage that the timing light is picking up interference or they are trying to cover up the fact that your ignition is firing when it's not supposed to. Just my thoughts. Anyway back to the real point, I definitely appreciate the suggestions. I think I will invest in a better timing light for the future but with this particular project I am content with essentially faking it till it runs right. Im sure some people will feel like this is a major no no but this is just an off road toy.

Bill is Correct.... The problem lies in the MSD (Multi-Spark) Part of the active system. Only cetin lights systems will filter it.

At this point I think I would just tune it by ear also....

Just my 2 cents

Oh ok... it has to filter the additional sparks going to the plug, I get it. Cool. Well anyway I believe ear/make my own timing mark it will be for the old W250. By the way with the Magnum 5.9 and a 650 carb she is a BEAST! Not to mention I did custom 3" stacks up through the bed with glass packs.

That should "talk" pretty good....
You Do know I'm a truck guy.. I like it alot

What I did was bought a non digital timing light from Advanced Auto Parts, for $60 and it worked fine.. The timing light I was talking about that wouldn't work on MSD was for digital or DIS ignition and because MSD is multi spark discharge if you prefer...It was bouncing all over the place...This timing light will make lunch for you if you hit the right button ,,LOL ..You could put it in 4 wheel drive have someone torque load the engine set the timing until it pings then back it of until it stops pinging....Bill